Internal-combustion engine



' E. J. A. SCHULTZ.

INTERNAL -COMBUSTION ENGINE.

' APPLICATION 'FILED sEPT.24, 191s.v

Patentd Jun 7, 1921# s sHEeTs-suzzr 1L E. 1. A. SCHULTZ.

INTERNAL COMBUSTION ENGINE. APPLICATION FILED sEPT.24, Is'I.

Patented June 7, 1921.

s sHIsET`-sHeET 2. i

v E. l. A. SCHULTZ. INTERNAL cmusTxoN ENGmE. l APPLICATION FILED SEPT. 24. 1918.

Patented June 7, 1921.

' 3 SHEETS-SHEET 3 Alm UNITED STATES EMILE JOSEPH AUGUSTIN SCI-IULTZ, OF PARIS, FRANCE.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent. Patented J 1111 '7, 1921.

Application led September 24, `1918. Serial No. 255,514.

To all 'whom t may concern.'

Be it known that I, EMILE JOSEPH AU- GUsrIN SCHULTZ, a citizen of the Republic of France, residing in Paris, France, have invented certain new and useful Improvements in Internal-Combustion Engines, of which the following is a specication.

|This invention relates to a system of distribution applicable to rotary internal com bustion engines having an odd number of cylinders arranged in star.

The distribution is brought about by means of two cams, one for the exhaust, the other for the admission, which act by means of suitable bosses on the rods of valves arranged on the circumference of a circle in two planes corresponding respectively with the cams. The duration of the admission and exhaust are determined by the respective eccentricities of the cams, which ec-:

' centricity causes the bosses to move on circumferences cutting those on which the rods of the valves lie at points comprising between them the desired angles.

Moreover, the cams are driven at such a speed in relation to the'speed of the engine that two consecutive bosses act on two valves of cylinders which should operate consecutively in times separated by intervals corresponding with the lapse of time which is necessary for the engine to turn through an angle equal to that which separates two consecutive cylinders.

The movement of the cams is transmitted to one of them by using its eccentricity by means of a toothed wheel xed on it which is driven by a gearfixed to the frame of the engine and the diameter of which is calculated to give to the said wheel a movement suitable for producing the relative speed desired. The other cam is entrained by the first by means of a smallconnecting rod.

`In the accompanying drawings .there is shown one mode of realizing the distribution according to this invention applied to .a rotary engine having seven cylinders operating in pairs so as to perform a complete cycle in two revolutions. l

Figure 1 is a diagrammatic front elevation of the whole of the distribution, the admission cam being hatched, sofar as it is visible, for the sake of clearness.

Fig. 2 is a digram showing how the second cam is entrained.

Fig. 3 is a section on line X-Xfof Fig. 1,;showing how the cams are driven.

The exhaust cam E and the admission cam A have each four bosses acting at the desired moment on the rods of valves of cylinders 1, 2, 3, 4, 5, 6, 7 owing to the positions of their centers 01 and 02 determined respectively by the bisecting lines ofthe angles corresponding with these periods.

The sliding rods vor tappets of the valves are'mounted in planes corresponding with those of the two cams and they are arranged in such a manner that when not displaced their ends traverse circles m of equal radius having their centers in the axis O 0f the engine. The latter turning from right to left (in the direction of the arrow f) andl the cams being eccentric, at the period represented in Fig. 1, namely the exhaust period on the right hand and the admission period on the left hand, the position is such that the sliding rods 1, 2, 3 and 4 can alone be in contact with the exhaust cam, and in particular 1 and 3, beneath which there is shown projection of the cam. For the same reason in the other series of sliding rods moimted in the admission plane only 5, 6 and 7 can be operated by the projections of the 'cam A.

From the foregoing it will be seen that each'valve rod can receive at maximum only one impulse per revolution, but from the particular arrangements used the rods are operated each at both revolutions in such a manner that the cylinders operate in the order 3, l, 6, 4, 2, 7, 5. To obtain this result the relative speed of the cams is suitably proportioned in relation to the engine and the number of bosses.

' In the example shown the exhaust cam E is drivenvby an internally toothed wheel b (Fig. 3) eccentric on the fixed shaft T of the motor to the same extent as the cam and itself driven' by an external gear a mounted co-axially with the revolving frame B of the engine, on which frame it is iixed. The diameter of this pinion is 7/8ths of that of the internally toothed wheel b. In consequence the latter and the cams have an angular movement whichvis in the same proportion to the angular speed of the engine. These several parts turn on fixed rings 0 so arranged as to reduce the friction; the con-V nection between the wheel b and the cam E may be by rods such as d, or a light sleeve co-axial with Y) and E.

-To the end that the cylinders may operate in the order already indicated, the cams have four bosses and are driven as has been described in the same direction as that in which the engine turns, but at a slow speed, so that they in effect rotate backward relatively to the engine at a speed fv equal to l/8th of that of the engine. Furthermore, the bosses have a form such that the degree of opening of the valves may be nearly constant during the whole period of the action or' the cam, taking into account the eccentricity of the controlling parts.

Under these conditions between cylinders 3 and l, separated by Q/Tths of the circumference there must be a difference of phase of 2/7ths and between l and 2 separated by l/Tth there must be a diierence of 6/7ths. In theiirs't case supposing that the exhaust begins at l under action of boss g, as indicated in Fig. l, it should have been already in progress at 3 under action of boss g1 for a time corresponding with a fraction of revolution equal to Now it has been seen that the cam is driven at a relative speed equal to 1/8 of that of the engine. It follows that when the engine has performed 2/7 of a revolution the cam will be behind it tothe extent of 2/56 of a revolution. This fraction just represents the difference between 2/7 and 1/4 and in consequence' the valves are controlled in this case by the. adjacent bosses at the desired moment.

But in the following revolution the cam will be behind the motor to the extent of 1/8 of 7 /7 of a revolution, that is to lsay 1/8 ofthe revolution. The rods 1 and 3 will then be opposite the spaces .between the bosses and the rods corresponding with the cylinders of even number` will be operated, thus complying with the necessary conditions.-

The operation is the same for the admission cam, but evidently at one revolution later; however, owing to the mode of driving this cam, which is shown in the diagram Fig. 2, where m a, m1 al, m2 n2, m3 n3 show iourpositions of the connecting rod i which drives the cam A, it is necessary to varythe length of the bosses. Those of greater lengthcorrespond with the period when the relative speed is a miximum and vice versa.

It will be seen that the system of control is particularly simple and light. it will be seen that the bosses of the cams engage the sliding rods of the valves at a very slow speedfso that shocks and damage to the parts are avoided and wear is considerably reduced. It is also to be remarked that, owing to these conditions of operating the control does not necessitate the use of rollers,

The invention is applicable to all rotary engines whatever .may be the number of Moreover, A

cylinders and the side of the polygonal star provided for the distribution; it suiiices in each case to correctly proportion the number of bosses and the relative speed of the cams.

Having thus fully described the nature of my invention and the best means I know of carrying the same into practical effect, l claim 1. Distributing mechanism tor rotary cylinder internal combustion engines having an odd number of cylinders, and valve tappets the ends of which are normally equidistant from the axis ol' rotation, which mechanism comprises a single admission cam, a single exhaust cam, said cams having rounded bosses for displacing the respective valve tappets, each cam being eccentric in relation tothe axis of the engine, and differential driving means for rotating said cams at a speed such that the relative speed between the cams and the engine is that requisite for determining admission and exhaust at the proper periods, the rounded bosses displacing the tappets by a sliding engagement.

2. Distributing mechanism for rotary cylinder internal combustion engines having an odd number oi" cylinders, which mechanism comprises a single admission cam and a single exhaust cam, said cams having rounded bosses, valve-operating rods normally equidistant from the axis of the engine, so that their ends tend to describe circles concentric to saidraxis, the said cams mounted eccentrically on the shaft of the engine, the eccentricity such that their bosses displace said rods only when moving beyond said circles, and diiiierential driving means for rotating said cams at a speed such that the relative speed between the cams and the engine is that requisite for determining admission and exhaust at the proper periods.

3).v Distributing mechanism for rotary cylinder internal combustion engines having an odd number of cylinders, which mechanism comprises a single admission cam and a single exhaust cam, said cams having rounded bosses, valve-operating means comprising tappets normallyfequidistant from the axis of the engine, so that they tend to describe circles concentric with said axis, the said cams mounted eccentrically on the shaft of the engine, with such eccentricity that their bosses move within said circles on one side and beyond them on the other side, and driving means for said cams comprising an internally toothed wheel mounted eccentrically on the sha-ft of the engine to turn thereon, a toothed wheel mounted to turn on the shaft of the engine coaxially with the framing of the engine andV fixed tothe said framing, the said toothed vwheel being llO of smaller diameter than the said` internally 130 toothed wheel and adapted to drive the latter, and a driving connection between the latter and said cams.

4c. Distributing mechanism for rotary cylinder internal combustion engines having an odd number of cylinders, which mechanism comprises a single admission cam and a single exhaust cam, said cams having bosses, valve-operating tappets normally equidistant Jfrom the axis of the engine, so that they tend to describe circles concentric with such axis, means whereby the said cams are mounted eccentrically on the shaft of the engine, their eccentricity such that their bosses on one side move beyond said circles and displace said tappets, and differential driving means for rotating one of said cams at such speed relatively to that of the engine for determining admission and exhaust at the proper periods, and means for driving the other of said cams from the iirst cam.

5. The combination of claim 4, the lastnamed driving means being a link connecting the cams, and the bosses on the linkdriven cam being of varying length to compensate for variations in speed of such cam.

In witness whereof, I have hereunto signed my name.

EMILE JOSEPH AUGUSTIN SCHULTZ. Witnesses:

JOHN F. SIMoNs, HENRI CARTIER. 

